Control mechanism for material handling apparatus



Oct. 19, 1965 G. P. KOCH 3,212,659

CONTROL MECHANISM FOR MATERIAL HANDLING APPARATUS Filed March 2'7, 1963 3 Sheets-Sheet 1 INVENTOR.

Oct. 19, 1965 G. P. KOCH 3,212,659

CONTROL MECHANISM FOR MATERIAL HANDLING APPARATUS Filed March 27, 1965 3 Sheets-Sheet 2 INVENTOR.

6602?? Prid? Oct. 19, 1965 cs. P. KOCH 3,212,659

CONTROL MECHANISM FOR MATERIAL HANDLING APPARATUS Filed March 27, 1963 3 Sheets-Sheet 3 4 7 i A? 1% S y 1%? W50 6 Kay a 9 w IN VENTOR @WfI/w M United States Patent CONTROL MECHANISM FOR MATERIAL HANDLING APPARATUS George P. Koch, Livonia, Mich, assignor to Massey- Ferguson Inc., Detroit, Mich a corporation of Maryland Filed Mar. 27, 1963, Ser. No. 268,295 17 Claims. (Cl. 214132) This invention relates to material handling apparatus such as tractor-mounted front end loaders, back-hoes and the like which typically include material handling means mounted on a tractor for lateral swinging movement relative thereto and, in particular, is characterized by an improved control means for controlling swinging movement of the material handling means.

Material handling apparatus of the type aforementioned typically include a main frame secured to a suitable prime mover, such as an agricultural or industrial tractor, a swing frame pivotally mounted on the main frame for lateral swinging movement relative thereto, material handling means including a bucket or other suitable implement carried by the swing frame for swinging movement therewith, and one or more ground-engaging stabilizer arm means adjustably pivotally mounted on the main frame for lateral swinging adjustment relative to the latter to any one of a plurality of preselectable ground-engaging stabilizing positions to stabilize the tractor or other prime mover vehicle during the material handling operations.

As will be apparent, in order to achieve maximum stabilization from such stabilizer arm means under various working conditions, it is highly desirable that the stabilizer arm means be capable of a relatively great range of lateral adjustment with respect to the main frame, and it is usually necessary to dispose the stabilizer arm means within the range of swinging movement of the swing frame and the material handling means carried thereby. As a result, the operator of the apparatus must exercise extreme care to discontinue swinging movement of the swing frame and the material handling means carried thereby when they approach one of the stabilizer arm means disposed within the range of swinging movement thereof; otherwise, impact occurs and severe damage may be done to the material handling means or the stabilizer arm means, or both. However, as will also be readily apparent to those acquainted with apparatus of this type, the operator thereof normally must devote substantially his full attention to the material handling means during the various digging, lifting, swinging and dumping cycles of the latter and quite often will not notice that he is manipulating the material handling means toward impact with one of the stabilizer arm means, thereby resulting in the damage aforementioned.

In view of the foregoing considerations, the present invention is directed to an improved material handling apparatus of the type aforementioned particularly characterized by control means controlling lateral swinging movement of the swing frame throughout the range of movement thereof, and being automatically operable to discontinue swinging movement thereof in response to the latter reaching a predetermined position relative to a stabilizer arm means disposed in any one of the plurality of prese lectable ground-engaging stabilizing positions thereof within the range of movement of the swing frame and the material handling means carried thereby.

More specifically in this regard, the aforementioned control means is particularly characterized by fluid pressure operated motor means operatively connected to the swing frame and operable to swing the latter throughout the range of movement thereof, a source of fluid under ice pressure, fluid circuit means communicating the motor means with the source, manually operable selector valve means in the aforementioned circuit means for controlling the flow of fluid through the latter for power swinging movement of the swing frame and the material handling means carried thereby, and control valve means in the aforementioned circuit means automatically operable to interrupt flow of fluid through the circuit means independently of operation of the selector valve means and in response to swinging movement of the swing frame to a predetermined position relative to the aforementioned stabilizer arm means disposed in any one of the pre-selectable stabilizing positions thereof within the range of swinging movement of the swing frame.

In its more specific aspects, the present invention is further characterized by the fact that the aforementioned control valve means comprises valve operating means engageable with the swing frame and being automatically positioned thereby in the aforementioned predetermined position thereof to interrupt flow of fluid through the circuit means and thereby automatically discontinue power swinging movement of the swing frame. In addition, the invention is further particularly characterized by means adjustably pivotally mounting the control valve means on the main frame of the apparatus, and means operatively connecting the stabilizing arm means to the control valve means to initially bodily adjust the physical location of the latter including the aforementioned valve operating means relative to any pre-selected stabilizing position of the stabilizer arm means and the range of swinging movement of the swing frame.

In order to facilitate an understanding of the invention, a preferred embodiment thereof will now be described with reference to the accompanying drawings in which:

FIGURE 1 is a top plan view of a material handling apparatus, specifically a back-hoe, illustrating a preferred embodiment of the invention;

FIGURE 2 is a side elevational view of the apparatus illustrated in FIGURE 1;

FIGURE 3 is an enlarged fragmentary sectional view taken on line 33 of FIGURE 2;

FIGURE 4 is an enlarged fragmentary sectional View taken on line 4-4 of FIGURE 3; and

FIGURE 5 is a schematic illustration of a fluid pressure system for controlling swinging movement of the swing frame of the apparatus.

Referring now to the drawings, and particularly FIG- URES 1 and 2, the numeral 10 generally indicating a suitable and conventional tractor comprising the usual forwardly-facing seat 12 for the vehicle driver, and a hollow main frame 14 suitably rigidly supported on the tractor substantially on the longitudinal centerline of the latter and projecting rearwardly therefrom to mount the backhoe apparatus indicated generally at 16 and a pair of stabilizer arm assembles respectively indicated generally at 18.

The back-hoe apparatus 16 comprises a swing frame 20 including a pivot post 22 suitably pivotally mounted in the vertically spaced brackets 24 fixed to the main frame 14 for lateral swinging movement relative thereto throughout an arcuate range of preferably approximately 180 or, in other words, approximately to either side of a centered position of the swing frame as illustrated in solid line in FIGURES 1 and 3. Resilient bumper means 26, only one of which is illustrated in FIGURE 3, are suitably mounted on laterally opposite side walls of main frame 14 for abutment with laterally opposed side walls of the swing frame as illustrated in dotted lines in FIGURE 3 to limit swinging movement of the latter approximately 90 to either side of the aforementioned centered position thereof. A pair of substantially identical cam plates 28 each including a plurality of cam steps as illustrated are fixed to and extend laterally from the pposite side walls of the swing frame 20 on opposite sides of the pivot post 22 for a purpose to appear more fully hereinafter. A seat assembly 30 and a control console 32 having a suitable number of valve operating levers 34 to Control various fluid pressure operated instrumentalities of the back-hoe apparatus are suitably mounted at the upper end of the pivot post so as to be pivotal in unison with the swing frame.

The back-hoe apparatus further comprises the usual boom 36 suitably pivotally connected as indicated at 38 to the swing frame 20 for pivotal movement relative thereto in vertical plane under the control of a suitable fluid pressure operated boom jack 40 having its cylinder element pivotally connected at 42 to the swing frame and its piston element pivotally connected at 44 to the boom. A dipper stick 46 is suitably pivotally connected at 48 to the boom for pivotal movement relative thereto in a substantially vertical plane under the control of the dipper jack 50 having its cylinder element suitably pivotally connected at 52 to the boom and its piston element suitably pivotally connected at 54 to the dipper stick. Finally, the bucket 56 is suitably pivotally connected to the dipper stick as indicated at 58 for pivotal movement relative thereto in a substantially vertical plane under the control of the bucket jack 60 having its cylinder element suitably pivotally connected at 62 to the dipper stick and its piston element suitably pivotally connected at 64 to the pivotal interconnection of drive linksj66 and 68 having their opposite ends respectively pivotally connected at 70 and 72 to the dipper stick and bucket, respectively.

The stabilizer arm assemblies 18 are identical in construction, and each comprises a pivotal mounting bracket 74 connected by a pivot pin 76 to a vertically spaced pair of support brackets 78 fixed to respective laterally spaced side walls of the main frame 14 for adjustable laterally swinging movement relative to the latter. A main stabilizing arm 80 is suitably pivotally connected as indicated at 82 to the bracket 74 and carriesr at its other end the pivotally mounted ground-engaging stabilizing shoe 84. A suitable fluid pressure operated'jack 86 has its cylinder element suitably pivotally connected as indicated at 88 to the bracket 74 and its piston element pivotally connected at 90 to the outer end of the main stabilizing arm 80. A keeper bracket 92 carried by the mounting bracket 74 is apertured for coaction with any one of three sets of aligned apertures in corresponding vertically spaced locking brackets 94 extending fromthe laterally spaced side wall of the main frame 14 so as to removably receive a lock pin 96 therethrough to independently lock the respective stabilizing arm assemblies in any one of three pre-selectable ground-engaging stabilizing positions as illustrated in full and dotted lines in FIGURE 1.

It will, of course, be apparent that a suitable fluid pressure system is associated with the apparatus and includes suitable valving controlled at the console 32 by the backhoe operator in seat assembly 30 to selectively supply and exhaust operating fluid to various ones of the boom jack 40, dipper jack 50, bucket jack 60and stabilizing jacks 86. Thus, such conventional valving may be manipulated by the back-hoe operator to raise and lower the boom 36 relative to the ground, to pivot the dipper stick 46 in a vertical plane relative to the boom, to pivot the bucket 56 on the end of the dipper stick during digging, carrying and dumping operations, and to lift the shoes 84 from the ground to permit, upon removal of the lock pin 96, lateral swinging movement and adjustment of the respective stabilizer arms 80 independently of each other to any one of three preselectable stabilizing positions projecting laterally outwardly and rearwardly from the main frame 14. Thus, it will be appreciated that once the stabilizer arms are mounted in position in accordance with the working condition presented, the jacks 86 will be operated to force the shoes 84 into the ground to stabilize the apparatus during operation of the back-hoe assembly.

It may again be noted at this juncture that the swing frame 20 and the material handling instrumentalities carried thereby and aforedescribed are preferably adapted for lateral swinging movement relative to the main frame, and any preselected position of the stabilizer arm assemblies 18, through an arcuate range of preferably approximately 180. Furthermore, and with reference to FIG- URES 1 and 3, it will be noted that such a range of movement of the swing frame and the material handling instrumentalities carried thereby overlaps the arcuate range of lateral adjustment of the respective stabilizer arm assemblies 18 at opposite ends of the range of movement of the swing frame. However, control means now to be described is provided in combination with the aforedescribed apparatus to control swinging movement of the swing frame 20 throughout its range of movement aforementioned, and to automatically discontinue swinging movement of the swing frame when it reaches a predetermined position relative to either one of the stabilizer arm assemblies 18 in any one of the pre-selectable stabilizing positions thereof to prevent damage to the apparatus.

Referring now particularly to FIGURE 5 and the schematic illustration of the fluid system for controlling swinging movement of the swing frame 20 through the entire range of movement thereof, it may be seen that such a system comprises a fluid reservoir 98 from which fluid is supplied to the pump 100 for delivery under pressure through conduit means 102 to an inlet port in a conventional manually operable selector valve assembly 104 having a return port for return of fluid through conduit 106 to the reservoir, the valve assembly being mounted on the control console 32 illustrated in FIGURE 2. The selector valve assembly 104 is shown as being of a conventional open-center type including two additional ports normally blocked from communication with the aforementioned ports with the valve assembly in its neutral position as shown, and are connected by the respective conduits 108 and 110 through respective ones of a pair of automatically operable control valve means indicated generally at 112 to the respective conduits 114 and 116 communicating with opposite ends of the cylinder 118 of a fluid pressure operated motor indicated generally at 120. The motor 120 further includes a pair of piston heads 122 connected to opposite ends of a piston rod 124 including a rack gear 126 thereon, all of which is reciprocably disposed within the cylinder 118. The rack gear meshingly engages a rotatable pinion 128 suitably coupled as indicated schematically at 130 in driving relation to the swing frame 20 and its pivot post 22.

With the manual selector valve 104 disposed in the neutral position as illustrated in FIGURE 5, fluid is locked in both of the conduits 108 and 110 and in the conduits 114 and 116 to maintain the double-headed piston and, hence, the swing frame and the material handling instrumentalities thereof stationary. However, upon manual shifting of the selector valve 104 to the left to a first operating position, it will be apparent that fluid under pressure is supplied by the pump to the conduit 108 and, in a manner to be described more fully hereinafter, through the associated control valve means 112 to the conduit 114 and one end of the fluid motor, fluid being exhausted from the other end thereof through the conduit 116, the associated control valve means 112 also in a manner to be described hereinafter, and the conduit 110 to the reservoir 98. In similar fashion, shifting of the selector valve to the right to a second operating position results in the conduits 110 and 116 being pressurized to supply fluid under pressure to the other end of the mo tor, while the opposite end thereof is exhausted through swing the swing frame 20 laterally in one or the other direction on the main frame of the vehicle.

Referring now particularly to FIGURES 3, 4 and 5, it may be observed that the control valve means 112 are disposed within the main frame 14 and are identical to each other in comprising a valve body 132 having a fitting 134 at one end thereof connected with a respective one of the conduits 108 or 110 communicating with the main selector valve 104, and another opposite fitting 136 communicating with a respective one of the conduits 114 and 116 communicating with respective ends of the motor cylinder 118. A .port 138 and one-way spring biased check valve 140 permit one-way communication between the fittings 134 and 136 and their respective associated conduits; that is, fluid flow from conduits 108 and 118 respectively to conduits 114 and 116. On the other hand, the fittings 136 and 134 are communicable through ports 142 and 144 in the valve body 132. A ball check valve 146 suitably seated on one end of a pin 148 controls oneway flow of fluid under certain conditions to be described from the fitting 136 through the ports 142 and 144 to the fitting 134 to communicate the associated conduits 114 and 116 to the respective conduits 108 and 110.

A valve operating plunger 150 is reciprocably slidably disposed within and through the open end of a bore 152 in the valve body 132, and a spring 154 extends between the base of the valve operating plunger and the head of the pin 148 to normally urge the latter to the left in FIGURE 4 to seat the ball check valve 146 in closing relation to the port 146. At the same time, the spring 154 biases the valve operating plunger to the right in FIG- URE 4 as limited by engagement of a shoulder thereon with a snap ring or the like 156 seated within the opening to the body bore 152. Thus, it will be understood that the spring 154 normally biases the pin 148 and the plunger 150 axially apart as limited by seating of the ball check valve 146 and engagement of the plunger with the snap ring 156 as illustrated in FIGURE 4.

The end of each valve operating plunger extends exteriorly of the valve body 132 and is suitably pivotally connected to one end of a link 158 having its other end pivotally connected to one end of a cam follower rod 160 suitably slidably mounted in a bearing member 162 so as to extend out of the main frame 14 toward the swing frame 20 and an associated cam plate 28 mounted mounted thereon. As will be pointed out hereinafter, with the valve bodies 132 disposed in any given fixed position, the respective cam follower rods 160 are positioned for engagement with various cam steps on the respective cam plates 28 to reciprocate the valve operating plunger 150 inwardly of the valve body bore 152 to control operation of the fluid system aforedescribed and swinging movement of the swing frame.

The respective control valve bodies 132 and their associated parts are suitably mounted on carriages 164 respectively pivotally connected as indicated at 166 within the main frame 14 for lateral swinging movement relative thereto. The carriages are additionally operatively pivotally connected to the respective stabilizer arm assemblies 18 as by means of the axially adjustable positioning rods 168 having their respective opposite ends suitably pivotally connected as indicated at 170 and 172 to the respective carriages 164 and a bracket carried by the respective stabilizer arm assemblies 18. Thus, it will be readily apparent that initial positioning of one or the other or both of the stabilizing arm assemblies 18 as previously described will initially bodily shift the physical location of the control valve assemblies 112 including the links 158 and cam follower rods 160 to an initial position corresponding to the position of their associated stabilizer arm assemblies, and in a predetermined relationship to the arcuate range of movement of the swing frame 20.

It will be apparent that initial positioning of the respective stabilizer arm assemblies 18 in any one of the preselectable positions thereof as indicated in full and dotted lines in FIGURE 1 will automatically initially position the control valve 112 with respect to the range of arcuate movement of the swing frame. Thus, with the respective stabilizer arm assemblies in the laterally innermost positions illustrated in dotted line in FIGURE 1, it will be readily apparent that the respective carriages 164 have been swung toward the swing frame to initially position the cam follower rods 160 in relatively close proximity to the path of movement of the cam plates 28 on the swing frame 20. On the other hand, initially disposing the stabilizer arm assemblies in the laterally outermost positions thereof as illustrated in dotted line in FIGURE 1 has the reverse effect of requiring a greater range of arcuate movement of the swing frame to either side of a centered position thereof before the cam plates 28 engage the cam follower rods 160.

In this regard, it will be observed at this juncture that the geometry of the control valves 112, the linkage connecting the latter to the respective stabilizer arm assemblies 18 and the relationship of the cam follower rods 160 thereto and to the path of swinging movement of the swing frame 20 will be such as to, in essence, initially locate the protruding ends of the rods 160 in .pre-selected positions relative to the positions of the respective stabilizer arm assemblies 18 and the path of swinging movement of the swing frame whereby, upon the swing frame swinging to such an extent relative to and toward an impact condition with one of the stabilizer arm assemblies, the cam steps of the respective cam plates 28 will successively engage the end of a rod 160 and gradually reciprocate the latter and the valve operating plunger 150 into the bore 152 to compress the spring 154 as will be described hereinafter.

In operation, it may be assumed that the swing frame 20 is disposed in a centered position with respect to its range of arcuate swinging movement as illustrated in full line in FIGURES 1 and 3, and that the respective stabilizer arm assemblies 18 are likewise disposed in the solid line positions of FIGURES 1 and 3 so as to project laterally rearwardly and outwardly from the main frame of the vehicle into a portion of the path of swinging movement of the swing frame to either side of the aforesaid center position. With the swing frame and the stabilizer arms so initially positioned, the control links 168 will initially bodily position the control valve assemblies 112 as previously described to dispose the ends of the cam follower rods 168 in a predetermined position with respect to the path of swinging movement of the swing frame 20 and the cam plates 28 carried thereby. In this regard, with the parts aforedescribed so disposed, the spring 154 disposed in the bore '152 of each control valve assembly will bias the valve operating plunger 150 outwardly of the bore of the valve body against the snap ring 156 to so initially position the rods 160.

Referring now particularly to FIGURES 3 through 5, it may now be assumed that the operator of the back-hoe manually shifts the selector valve 104 to the left in FIGURE 5 to pressurize conduit 108 and connected conduit with the reservoir 98. As a result, fluid under pressure in conduit 108 enters the fitting 134 of its associated control valve assembly 112, shifts the check valve off of the port 138 and flows therethrough into the fitting 136 and into the conduit 114 to one end of the motor 120 to cause the piston to reciprocate in one direction to drive the pinion 128 and swing the swing frame 20 and the instrumentalities carried thereby clockwise in FIGURES 3 and 5. As the motor so operates, fluid is exhausted from the other end thereof through the conduit 116 into the fitting 136 of its associated control valve assembly. At this time, depending upon the position of the valve operating plunger within the bore 152, the fluid is either permitted to flow through the port 142 past the check valve 146 into the port 144 and the fitting 134 to the conduit 110 and to 7 reservoir or, due to the pressure of the spring 154, the check valve 146 is held tightly upon the port 142 to interrupt any such flow and hence discontinue operation of the motor 120. Thus, with the plunger b in an extreme outward position with respect to the valve body 132 as illustrated in FIGURE 4 and a position it assumes when it has not yet engaged its associated cam plate 28, the force of the spring 154 is insuflicient to maintain the check valve 146 on its seat on the port 142 in opposition to the fluid flowing from the motor 120 back to the reservoir as previously described. Consequently, the fluid circuit remains open from the conduit 116 through the check valve .146, conduit 110 and selector valve 104 to the reservoir.

As the swing frame moves under such fluid power clockwise toward the stabilizer arm assembly 18 on the right rear side of the main frame, one or the other of the cam steps on the associated cam plate 28 will ultimately engage the projecting end of the rod 160 of the associated control valve assembly 112 and, in response to continued swinging movement of the swing frame clockwise, will gradually reciprocate the valve operating plunger 150 inwardly of the valve body bore 152 toward the ball check 146, thereby gradually compressing the spring 154. However, notwithstanding gradual inward reciprocation of the valve operating plunger 150 and gradual compression of the spring 154, exhaust fluid is still permitted to flow from the conduit 116 past the check valve 146 into the conduit 110 and the resevoir as previously described until such time as, in effect, an impact or collision situation is presented by reason of the swing frame 20 reaching a predetermined position with respect to the associated stabilizer arm assembly.

Thus, at such a predetermined position of the swing frame, it will be understood that the valve operating plunger 150 has now been reciprocated inwardly within the valve body bore 152 due to coaction with the steps on a cam plate 28 to such an extent as to compress the spring 154 to prevent the ball check 146 from passing any substantial amount of fluid from the conduit 116 into the conduit 110 and to reservoir. At this time, even through the manual operable selector valve 104 is still in an open position pressurizing the conduit 108 and exhausting conduit 110 as previously assumed, the motor 120 is stopped and the swing frame is stopped from swinging any further. In this regard, due to the gradual reciprocation of the valve operating plunger 150 and gradual compres-sion of the spring 154' there is provided a cushioning effect on the hydraulic system and the swing frame 20 as it approaches and reaches the aforementioned predetermined position beyond which it is stopped from moving to prevent collision with the stabilizing arm means.

Naturally, in the event that the manually operable selector valve 104 is shifted to the right in FIGURE 5 to its other operating position, fluid under pressure is supplied from the pump 100 to the conduit 110 and, through its associated control valve means 112, to the conduit 1 16 to reciprocate the motor 120 and to swing the swing frame 20 in the opposite direction, fluid being exhausted from the other end of the motor means through the conduit 114, its associated control valve means 112 and conduit 108 to the reservoir. During this action, the control valve means communicating conduit 114 with conduit 108 will function automatically to interrupt the flow of exhaust fluid from the motor to the reservoir when the swing frame has reached the predetermined position with respect to the selected position of the associated stabilizer arm means to prevent impact as aforementioned.

It is significant to note, at this point, that the automatic interruption of the fiow of fluid in the fluid pressure system as aforedcscribed in order to avoid impact between the swing frame or the instrumentalities carried thereon and one or the other or both of the stabilizer arm assemblies 18 is not limited to any particular position of the swing frame 20. In other words, due to the fact that the control valve assemblies 112 and their associated operating elements are initially bodily shifted in direct relation to the positions of their associated stabilizer arm assemblies and the range of arcuate movement of the swing frame 20, the automatic interruption of further swinging movement of the swing frame will be accomplished as aforedescribed irrespective of what selected position the stabilizer arms may be in within the range of movement of the swing frame. Futhermore, each stabilizer arm assembly 18 and its associated control valve mechanism 112' are independently positionable with respect to the other. Thus, although swinging movement of the swing frame in one direction from the centered position thereof may be interrupted at one angle to one side of such centered position, its swinging movement to the other side of such centered position may be interrupted at a greater or smaller angle. Therefore, it will be readily apparent that the present swing frame control mechanism is completely flexible in automatically adapting its operation to any one of the plurality of preselectable ground-engaging stabilizing positions available for ach one of the stabilizing arm assemblies as determined by the particular working conditions encountered, and each setting of each stabilizer arm is completely independent from the setting of the other.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a material handling apparatus of the type including main frame means, swing frame means pivotally mounted on said main frame means for lateral swinging movement relative thereto, material handling means carried by said swing frame means for swinging movement therewith, and ground-engaging stabilizer arm means adjustably pivotally mounted on said main frame means for lateral swinging adjustment relative thereto among a plurality of pre-selectable ground-engaging stabilizing positions within the range of swinging movement of said swing frame means; the improvement comprising means controlling swinging movement of said swing frame means throughout the range of movement thereof, and means automatically operable to discontinue swinging movement of said swing frame means in a predetermined position thereof relative to said stabilizer arm means in response to any one of said stabilizing positions of the latter.

2. In a material handling apparatus of the type including main frame means, swing frame means pivotally mounted on said main frame means for lateral swinging movement relative thereto, and material handling means carried by said swing frame means for swinging movement therewith; the improvement comprising power operated means operatively connected to said swing frame means and operable to swing the latter throughout the range of movement thereof, and control means controlling operation of said power operated means and being automatically operable to discontinue operation of the latter in response to swinging movement of said swing frame means to any one of a plurality of adjustably predeterminable positions thereof relative to said main frame means.

3. In a material handling apparatus of the type including main frame means, swing frame means pivotally mounted on said main frame means for laterial swinging movement relative thereto, material handling means carried by said swing frame means for swinging movement therewith, and ground-engaging stabilizer arm means adjustably pivotally mounted on said main frame means for lateral swinging adjustment relative thereto among a plurality of pre-selectable ground-engaging stabilizing positions within the range of swinging movement of said swing frame means; the improvement comprising fluid pressure operated means operatively connected to said swing frame means and operable to swing the latter throughout the range of movement thereof, and control valve means controlling operation of said fluid pressure operated means and being automatically operable to discontinue operation of the latter in response to swinging movement of said swing frame means to a predetermined position relative to said stabilizer arm means in any one of said stabilizing positions of the latter.

4. The material handling apparatus according to claim 3 wherein said control valve means has a first operating position permitting operation of said fluid pressure operated means and a second operating position interrupting operation thereof, and further comprising means normally urging said control valve means toward said first position thereof, and means for automatically moving said control valve means to said second position thereof in response to swinging movement of said swing frame means to said predetermined position thereof.

5. The material handling apparatus according to claim 3 wherein said control valve means comprises valve operating means engageable with said swing frame means and automatically operable in said predetermined position of the latter to interrupt operation of said fluid pressure operated means.

6. The material handling apparatus according to claim 3 wherein said control valve means comprises valve operating means engageable with said swing frame means and automatically operable in said predetermined position of the latter to interrupt operation of said fluid pressure operated means, and further comprising means adjustably mounting said control valve means on said main frame means, and means operatively connecting said stabilizing arm means to said control valve means to adjust tht position of the latter including said valve operating means relative to a preselected position of said stabilizer arm means and the range of swinging movement of said swing frame means.

7. In a material handling apparatus of the type including main frame means, swing frame means pivotally mounted on said main frame means for lateral swinging movement relative thereto, and material handling means carried by said swing frame means for swinging movement therewith; the improvement comprising fluid pressure operated motor means operatively connected to said swing frame means and operable to swing the latter throughout the range of movement thereof, a souce of fluid under pressure, fluid circuit means communicating said motor means and said source, manually operable selector valve means in said circuit means controlling the flow of fluid through the latter, and control valve means in said circuit means automatically operable to interrupt flow of fluid therethrough independently of said selector valve means in response to swinging movement of said swing frame means to any one of a plurality of predeterminable positions thereof relative to said main frame means.

8. In a material handling apparatus of the type including main frame means, swing frame means pivotally mounted on said main frame means for lateral swinging movement relative thereto, material handling means carried by said swing frame means for swinging movement therewith, and ground-engaging stabilizer arm means adjustably pivotally mounted on said main frame means for lateral swinging adjustment relative thereto among a plurality of pre-selectable ground-engaging stabilizing positions within the range of swinging movement of said swing frame means; the improvement comprising fluid pressure operated motor means operatively connected to said swing frame means and operable to swing the latter throughout the range of movement thereof, a source of fluid under pressure, fluid circuit means communicating said motor means and said source, manually operable selector valve means in said circuit means controlling the flow of fluid through the latter, and control valve means in said circuit means automatically operable to interrupt flow of fluid therethrough independently of said selector valve means in response to swinging movement of said swing frame means to a predetermined position relative to said stabilizer arm means in any one of said stabilizing positions of the latter.

9. The material handling apparatus according to claim 8 wherein said control valve means has a first operating position permitting flow of fluid through said circuit means and a second operating position interrupting flow of fluid therethrough, and further comprising means normally urging said control valve means toward said first position thereof, and means for automatically moving said control valve means to said second position thereof in response to swinging movement of said swing frame means to said predetermined position thereof.

10. The material handling apparatus according to claim 8 wherein said control valve means has a first operating position permitting flow of fluid through said circuit means and a second operating position interrupting flow of fluid therethrough, and further comprising means nor-mally urging said control valve means toward said first position thereof, and means for automatically moving said control valve means gradually to said second position thereof in response to swinging movement of said swing frame toward and to said predetermined position thereof.

11. The material handling apparatus according to claim 8 wherein said control valve means comprises valve operating means engageable with said swing frame means and automatically operable in said predetermined position of the latter to interrupt flow of fluid through said circuit means.

12. The material handling apparatus according to claim 8 wherein said control valve means comprises valve operating means engageable with said swing frame means and automatically operable in said predetermined position of the latter to interrupt flow of fluid through said circuit means, and further comprising means adjustably mounting said control valve means on said main frame means, and means operatively connecting said stabilizing arm means to said control valve means to adjust the position of the latter including said valve operating means relative to a preselected position of said stabilizer arm means and the range of swinging movement of said swing frame means.

13. The material handling apparatus according to claim 8 wherein said control valve means comprises a valve body, a check valve controlling the flow of fluid through said body, a valve operator movably mounted within said body and engageable with said swing frame means, spring means acting between said valve operator and said check valve, said valve operator having a first operating position in which said spring mean-s permits fluid t-o flow past said check valve and being gradually movable upon engagement with said swing frame means to a second operating position compressing said spring means to prevent flow of fluid past said check valve in said predetermined position of said swing frame.

14. The material handling apparatus according to claim 8 wherein said control valve means comprises a valve body, a check valve controlling the flow of fluid through said body, a valve operator movably mounted within said body and engageable with said swing frame means, spring means acting between said valve operator and said check valve, said valve operator having a first operating position in which said spring means permits fluid to flow past said check valve and being gradually movable upon engagement with said swing frame means to a second operating position compressing said spring means to prevent flow of fluid past said check valve in said predetermined position of said swing frame; said apparatus further comprising means adjusta bly mounting said valve body on said main frame means, and means operatively connecting said stabilizing arm means to said valve body to adjust the position of the latter including said valve operator relative to a preselected position of said stabilizer arm means and the range of swinging movement of said swing frame means.

15. In a material handling apparatus of the type including a main frame, a swing frame pivotally mounted on said main frame for lateral swinging movement relative thereto in an arcuate range of approximately 180, material handling means carried by said swing frame for swinging movement therewith, and a pair of ground-engaging stabilizer arm means respectively adjustably pivotally mounted on said main frame on opposite sides of the pivot axis of said swing frame for lateral swinging adjustment relative to said main frame among a plurality of preselectable ground-engaging stabilizing positions within the arcuate range of swinging movement of said swing frame; the improvement comprising fluid pressure operated motor means operatively connected to said swing frame and operable to swing the latter throughout said range of movement thereof, a source of fluid under pressure, a pair of con-' duit means communicating said motor means and said source, manually operable selector valve means controlling simultaneous supply of fluid from said source through one of said conduit means to said motor means and exhaust of fluid from said motor means through the other of said conduit means to said source, and control valve means in each of said conduit means and each being automatically operable to interrupt exhaust of fluid therethrough to saidsource independently of said selector valve means in response to swinging movement of said swing frame to a predetermined position relative to one of said stabilizer arm means in any oneof said stabilizing positions of the latter.

16. The material handling apparatus according to claim 15 wherein each of said control valve means comprises a valve body, a check valve controlling the flow of fluid through said body, a valve operator movably mounted within said body and engageable with said swing frame, spring means acting between said valve operator and said check valve, said valve operator having a first operating position in which said spring means permits fluid to flow past said check valve and being gradually movable upon engagement with said swing frame to a second operating position compressing said spring means to prevent flow of fluid past said check valve in said predetermined position of said swing frame.

17. The material handling apparatus according to claim 15 wherein each of said control valve means comprises a valve body, a check valve controlling the flow of fluid through said' body, a valve operator movably mounted within said body and engageable with said swing frame, spring means acting between said valve operator and said check valve, said valve operator having a first operating position in which said spring means permits fluid to flow past saidcheck valve and being gradually movable upon engagement with said Swing frame to a second operating position compressing said spring means to prevent flow of fluid past said check valve in said predetermined .position of said swing frame; said apparatus further comprising means adjustably pivota-lly mounting said respective valve bodies on said main frame, and means operatively connecting said respective stabilizing arm means to said respective valve bodies to adjust the positions of the latter including their respective valve operators relative to preselected positions of said stabilizer arm means and the range of swinging movement of said swing frame.

References Cited by the Examiner UNITED STATES PATENTS 2,218,818 10/ 4,0 Harrington -52 2,376,019 5/45' Thomas 212-39 2,903,145 9/59 Brinkel 2l4-l38 HUGO O. SCHULZ, Primary Examiner. 

1. IN A MATERIAL HANDLING APPARATUS OF THE TYPE INCLUDING MAIN FRAME MEANS, SWING FRAME MEANS PIVOTALLY MOUNTED ON SAID MAIN FRAME MEANS FOR LATERAL SWINGING MOVEMENT RELATIVE THERETO, MATERIAL HANDLING MEANS CARRIED BY SAID SWING FRAME MEANS FOR SWINGING MOVEMENT THEREWITH, AND GROUND-ENGAGING STABILIZER ARM MEANS ADJUSTABLY PIVITALLY MOUNTED ON SAID MAIN FRAME MEANS FOR LATERAL SWINGING ADJUSTMENT REALTIVE THERETO AMONG A PLURALITY OF PRE-SELECTABLE GROUND-ENGAGING STABILIZING POSITIONS WITHIN THE RANGE OF SWINGING MOVEMENT OF SAID SWING FRAME MEANS; THE IMPROVEMENT COMPRISING MEANS CONTROLLING SWINGING MOVEMENT OF SAID SWING FRAME MEANS THROUGHOUT THE RANGE OF MOVEMENT THEREOF, AND MEANS AUTOMATICALLY OPERABLE DISCONTINUE SWINGING MOVEMENT OF SAID SWING FRAME MEANS IN A PREDETERMINED POSITION THEREOF RELATIVE TO SAID STABILIZER ARM MEANS IN REPSONSE TO ANY ONE OF SAID STABILIZING POSITIONS OF THE LATTER. 